I finally succumbed to the advice of many, many Canon portrait shooters and bought a used EF 135mm/f2L yesterday. All I can say is... WOW. I used it the afternoon on headshot interviews with my 5D3 and am putting up a few video frame grabs right from the timeline.

The quick setup is a one-light key (Lowel Omni w/ shoot-through umbrella) and a Lowel Pro hairlight/rim on opposite side. Shot wide open at ISO 100.

I tried this lens after seeing this post. For me, the lack of IS was a dealbreaker. You couldn't touch the lens to focus or adjust without massive shake. Useless on a slider, and only good on a tripod if you plain ole don't touch it. I like the focal length and the bokeh is nice, but I gotta have IS and my 70-200 fits that nicely.
Bill

The classic use of the 135/2L is for photos at basketball games. That extra stop lets you cut the motion blur in half under low light. Or, as shown above, get an extra stop of blur in shallow DOF portraits.

If I want portrait shots in a restaurant or bar, give me the f/2 lens. (The 35/1.4L is my "restaurant glass".)

But for video, the lack of IS and the difficulty of focusing at f/2 make this lens a bit less practical. (You need a tripod and still-ish subject.)

The 135/2 wins the size/weight/stealth battle though. I find the 70-200/2.8L IS II a bit cumbersome and flashy out on the street.

I don't know.... Personally, I find that shallow depth of field too much and unnatural-looking. I like to have a little blurriness in the background, but there comes a point when it's too much and looks 'forced'...

For video, I like to use the stock 24-105mm lens, fairly tight. F4 gives you some DOF blurriness, but not too much, and the IS is great for handheld shots...

I agree with Ben. I like a little blurriness but not too much. That way you still 'feel' them in the room rather than it looking like a greenscreen key against a still shot background that has been through photoshop or something.

If you want IS - and I agree its very important for any handheld video work - also consider the Canon 100mmf2.8 Macro with its amazing hybrid image stabilisation. Its smaller and lighter than my Canon 70-200mm and another option. Beautiful lens and of course the macro ability comes in handy too!

Good points, folks. 90% of my paying work is seated interviews, and this lens is my new "go-to". I can establish with a wider shot on the EF 85mm/f1.8 and then cut to the 135mm/f2L. The lack of IS in either lens doesn't concern me for these shoots, as my subject doesn't move and I never touch the cam once it's rolling. I use my EF 24-105mm/f4L IS anytime I'm off the sticks, and the footage cuts together nicely with those lenses.

Lack of IS on this lens is a deal-breaker for many, and is understandable. I didn't have the budget for a Mark II 70-200mm/f2.8L IS. I own the 70-200/f4 IS version that I paid $900 for, and I paid $825 for the 135mm lens. Even combined, I couldn't touch a MkII... and the MkI is not really comparable in terms of sharpness wide-open, and both are still a stop slower than this lens. Other shooters will make other choices.

While some won't appreciate super-shallow DOF, you can always stop-down fast glass. You can't open-up slow glass. The shallow DOF is helpful when I don't have a ton of time to set-up a room, or am shooting in less-than-ideal places. The viewer's eye is drawn to the subject's eyes, where it belongs.

Attached is another screen grab of an interview in a cramped conference room. The wall behind the gentleman is just behind his chair. The gilded tree is actually a prop that they will use on-stage at the event, so they wanted it in the frame for the event film.

And amen, Jon, this lens is an indoor sports dream. Even with my 1.4xII extender, I have a 189mm/f2.8 and that's some fast, contrasty glass! On the sidelines, I can even shoot nighttime football games at reasonable shutter/ISO combos... and, of course, WISH I had a 300mm/f4!

It seems to me that shallow DOF usually only gets criticized by other photographers/videographers, but most clients really love it. As Brian points out, it's a great way to de-emphasize a boring or distracting background. Sometimes you have to shoot an interview on location and you really don't have an interesting or appropriate background, so it sure is handy to just be able to turn it to mush and call it art.
If every shot looks the same, that's just lazy... but the technique can be very useful and beautiful. If this is what works for you and makes your clients happy, you can't beat these fast lenses!

But you have to be careful too, if you have a subject that likes to lean back and forth while they talk, focus is going to be all over the place. When I have to deal with that, my SmallHD monitor with the awesome focus-assist is solid gold. Some subtle camera movement with my hand on the focus barrel and I can follow them all day. Can't recommend it enough! If shallow DOF is your thing, get one of these monitors and your life will be complete!

The 135L must be a dream for seated interviews. I use the ZE 85/1.4 (similar DOF as the 135L) and while I don't go wide open, having a fast lens means that stopping down a stop puts the lens in its sweet spot, compared to running a slow lens at the edge of its performance.

At work, we also have the 70-200/2.8L IS II, and it rocks for events, but I have yet to use it for a seated interview. It really is a killer lens with fantastic performance wide open, but it's much more expensive, large, heavy, and flashy compared to the 135L. That's not such a problem for an indoor, tripod use, but for street photos, I'd rather have the 135 than the zoom. When I want IS, the 100L is my "stealth" solution.